164 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 6 



EXPLANATION OF PLATE 19 



Figs. 



1. Elphidium simplex Cushman. X 85. a, side view; h, aper- 

 tural view. 



2,4. ? Elphidium incertum (Williamson), var. lene Cushman 

 and McCulloch, new variety. 2, Holotype. X 85. 4, X 85. 



3, 5. Elphidium tumidum Natland. X 45. aa, side views ; bb, 

 apertural views. 



6,8. Elphidium frigidum Cushman. 6, X 45. a, side view; b, 

 apertural view. 8, X 28. 



7. Elphidium articulatum (d'Orbigny). X 28. a, side view; 

 b, apertural view. 



9. Elphidium translucens Natland. X 35. a, side view; b, 

 apertural view. 



10, 11. Elphidium spinatum Cushman and Valentine. X 40. a, side 

 view; b, apertural view. 



